1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef __LINUX_NETFILTER_H 3 #define __LINUX_NETFILTER_H 4 5 #include <linux/init.h> 6 #include <linux/skbuff.h> 7 #include <linux/net.h> 8 #include <linux/if.h> 9 #include <linux/in.h> 10 #include <linux/in6.h> 11 #include <linux/wait.h> 12 #include <linux/list.h> 13 #include <linux/static_key.h> 14 #include <linux/netfilter_defs.h> 15 #include <linux/netdevice.h> 16 #include <net/net_namespace.h> 17 18 #ifdef CONFIG_NETFILTER 19 static inline int NF_DROP_GETERR(int verdict) 20 { 21 return -(verdict >> NF_VERDICT_QBITS); 22 } 23 24 static inline int nf_inet_addr_cmp(const union nf_inet_addr *a1, 25 const union nf_inet_addr *a2) 26 { 27 return a1->all[0] == a2->all[0] && 28 a1->all[1] == a2->all[1] && 29 a1->all[2] == a2->all[2] && 30 a1->all[3] == a2->all[3]; 31 } 32 33 static inline void nf_inet_addr_mask(const union nf_inet_addr *a1, 34 union nf_inet_addr *result, 35 const union nf_inet_addr *mask) 36 { 37 result->all[0] = a1->all[0] & mask->all[0]; 38 result->all[1] = a1->all[1] & mask->all[1]; 39 result->all[2] = a1->all[2] & mask->all[2]; 40 result->all[3] = a1->all[3] & mask->all[3]; 41 } 42 43 int netfilter_init(void); 44 45 struct sk_buff; 46 47 struct nf_hook_ops; 48 49 struct sock; 50 51 struct nf_hook_state { 52 unsigned int hook; 53 u_int8_t pf; 54 struct net_device *in; 55 struct net_device *out; 56 struct sock *sk; 57 struct net *net; 58 int (*okfn)(struct net *, struct sock *, struct sk_buff *); 59 }; 60 61 typedef unsigned int nf_hookfn(void *priv, 62 struct sk_buff *skb, 63 const struct nf_hook_state *state); 64 struct nf_hook_ops { 65 /* User fills in from here down. */ 66 nf_hookfn *hook; 67 struct net_device *dev; 68 void *priv; 69 u_int8_t pf; 70 unsigned int hooknum; 71 /* Hooks are ordered in ascending priority. */ 72 int priority; 73 }; 74 75 struct nf_hook_entry { 76 nf_hookfn *hook; 77 void *priv; 78 }; 79 80 struct nf_hook_entries_rcu_head { 81 struct rcu_head head; 82 void *allocation; 83 }; 84 85 struct nf_hook_entries { 86 u16 num_hook_entries; 87 /* padding */ 88 struct nf_hook_entry hooks[]; 89 90 /* trailer: pointers to original orig_ops of each hook, 91 * followed by rcu_head and scratch space used for freeing 92 * the structure via call_rcu. 93 * 94 * This is not part of struct nf_hook_entry since its only 95 * needed in slow path (hook register/unregister): 96 * const struct nf_hook_ops *orig_ops[] 97 * 98 * For the same reason, we store this at end -- its 99 * only needed when a hook is deleted, not during 100 * packet path processing: 101 * struct nf_hook_entries_rcu_head head 102 */ 103 }; 104 105 static inline struct nf_hook_ops **nf_hook_entries_get_hook_ops(const struct nf_hook_entries *e) 106 { 107 unsigned int n = e->num_hook_entries; 108 const void *hook_end; 109 110 hook_end = &e->hooks[n]; /* this is *past* ->hooks[]! */ 111 112 return (struct nf_hook_ops **)hook_end; 113 } 114 115 static inline int 116 nf_hook_entry_hookfn(const struct nf_hook_entry *entry, struct sk_buff *skb, 117 struct nf_hook_state *state) 118 { 119 return entry->hook(entry->priv, skb, state); 120 } 121 122 static inline void nf_hook_state_init(struct nf_hook_state *p, 123 unsigned int hook, 124 u_int8_t pf, 125 struct net_device *indev, 126 struct net_device *outdev, 127 struct sock *sk, 128 struct net *net, 129 int (*okfn)(struct net *, struct sock *, struct sk_buff *)) 130 { 131 p->hook = hook; 132 p->pf = pf; 133 p->in = indev; 134 p->out = outdev; 135 p->sk = sk; 136 p->net = net; 137 p->okfn = okfn; 138 } 139 140 141 142 struct nf_sockopt_ops { 143 struct list_head list; 144 145 u_int8_t pf; 146 147 /* Non-inclusive ranges: use 0/0/NULL to never get called. */ 148 int set_optmin; 149 int set_optmax; 150 int (*set)(struct sock *sk, int optval, void __user *user, unsigned int len); 151 #ifdef CONFIG_COMPAT 152 int (*compat_set)(struct sock *sk, int optval, 153 void __user *user, unsigned int len); 154 #endif 155 int get_optmin; 156 int get_optmax; 157 int (*get)(struct sock *sk, int optval, void __user *user, int *len); 158 #ifdef CONFIG_COMPAT 159 int (*compat_get)(struct sock *sk, int optval, 160 void __user *user, int *len); 161 #endif 162 /* Use the module struct to lock set/get code in place */ 163 struct module *owner; 164 }; 165 166 /* Function to register/unregister hook points. */ 167 int nf_register_net_hook(struct net *net, const struct nf_hook_ops *ops); 168 void nf_unregister_net_hook(struct net *net, const struct nf_hook_ops *ops); 169 int nf_register_net_hooks(struct net *net, const struct nf_hook_ops *reg, 170 unsigned int n); 171 void nf_unregister_net_hooks(struct net *net, const struct nf_hook_ops *reg, 172 unsigned int n); 173 174 /* Functions to register get/setsockopt ranges (non-inclusive). You 175 need to check permissions yourself! */ 176 int nf_register_sockopt(struct nf_sockopt_ops *reg); 177 void nf_unregister_sockopt(struct nf_sockopt_ops *reg); 178 179 #ifdef HAVE_JUMP_LABEL 180 extern struct static_key nf_hooks_needed[NFPROTO_NUMPROTO][NF_MAX_HOOKS]; 181 #endif 182 183 int nf_hook_slow(struct sk_buff *skb, struct nf_hook_state *state, 184 const struct nf_hook_entries *e, unsigned int i); 185 186 /** 187 * nf_hook - call a netfilter hook 188 * 189 * Returns 1 if the hook has allowed the packet to pass. The function 190 * okfn must be invoked by the caller in this case. Any other return 191 * value indicates the packet has been consumed by the hook. 192 */ 193 static inline int nf_hook(u_int8_t pf, unsigned int hook, struct net *net, 194 struct sock *sk, struct sk_buff *skb, 195 struct net_device *indev, struct net_device *outdev, 196 int (*okfn)(struct net *, struct sock *, struct sk_buff *)) 197 { 198 struct nf_hook_entries *hook_head = NULL; 199 int ret = 1; 200 201 #ifdef HAVE_JUMP_LABEL 202 if (__builtin_constant_p(pf) && 203 __builtin_constant_p(hook) && 204 !static_key_false(&nf_hooks_needed[pf][hook])) 205 return 1; 206 #endif 207 208 rcu_read_lock(); 209 switch (pf) { 210 case NFPROTO_IPV4: 211 hook_head = rcu_dereference(net->nf.hooks_ipv4[hook]); 212 break; 213 case NFPROTO_IPV6: 214 hook_head = rcu_dereference(net->nf.hooks_ipv6[hook]); 215 break; 216 case NFPROTO_ARP: 217 #ifdef CONFIG_NETFILTER_FAMILY_ARP 218 if (WARN_ON_ONCE(hook >= ARRAY_SIZE(net->nf.hooks_arp))) 219 break; 220 hook_head = rcu_dereference(net->nf.hooks_arp[hook]); 221 #endif 222 break; 223 case NFPROTO_BRIDGE: 224 #ifdef CONFIG_NETFILTER_FAMILY_BRIDGE 225 hook_head = rcu_dereference(net->nf.hooks_bridge[hook]); 226 #endif 227 break; 228 #if IS_ENABLED(CONFIG_DECNET) 229 case NFPROTO_DECNET: 230 hook_head = rcu_dereference(net->nf.hooks_decnet[hook]); 231 break; 232 #endif 233 default: 234 WARN_ON_ONCE(1); 235 break; 236 } 237 238 if (hook_head) { 239 struct nf_hook_state state; 240 241 nf_hook_state_init(&state, hook, pf, indev, outdev, 242 sk, net, okfn); 243 244 ret = nf_hook_slow(skb, &state, hook_head, 0); 245 } 246 rcu_read_unlock(); 247 248 return ret; 249 } 250 251 /* Activate hook; either okfn or kfree_skb called, unless a hook 252 returns NF_STOLEN (in which case, it's up to the hook to deal with 253 the consequences). 254 255 Returns -ERRNO if packet dropped. Zero means queued, stolen or 256 accepted. 257 */ 258 259 /* RR: 260 > I don't want nf_hook to return anything because people might forget 261 > about async and trust the return value to mean "packet was ok". 262 263 AK: 264 Just document it clearly, then you can expect some sense from kernel 265 coders :) 266 */ 267 268 static inline int 269 NF_HOOK_COND(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk, 270 struct sk_buff *skb, struct net_device *in, struct net_device *out, 271 int (*okfn)(struct net *, struct sock *, struct sk_buff *), 272 bool cond) 273 { 274 int ret; 275 276 if (!cond || 277 ((ret = nf_hook(pf, hook, net, sk, skb, in, out, okfn)) == 1)) 278 ret = okfn(net, sk, skb); 279 return ret; 280 } 281 282 static inline int 283 NF_HOOK(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk, struct sk_buff *skb, 284 struct net_device *in, struct net_device *out, 285 int (*okfn)(struct net *, struct sock *, struct sk_buff *)) 286 { 287 int ret = nf_hook(pf, hook, net, sk, skb, in, out, okfn); 288 if (ret == 1) 289 ret = okfn(net, sk, skb); 290 return ret; 291 } 292 293 static inline void 294 NF_HOOK_LIST(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk, 295 struct list_head *head, struct net_device *in, struct net_device *out, 296 int (*okfn)(struct net *, struct sock *, struct sk_buff *)) 297 { 298 struct sk_buff *skb, *next; 299 struct list_head sublist; 300 301 INIT_LIST_HEAD(&sublist); 302 list_for_each_entry_safe(skb, next, head, list) { 303 list_del(&skb->list); 304 if (nf_hook(pf, hook, net, sk, skb, in, out, okfn) == 1) 305 list_add_tail(&skb->list, &sublist); 306 } 307 /* Put passed packets back on main list */ 308 list_splice(&sublist, head); 309 } 310 311 /* Call setsockopt() */ 312 int nf_setsockopt(struct sock *sk, u_int8_t pf, int optval, char __user *opt, 313 unsigned int len); 314 int nf_getsockopt(struct sock *sk, u_int8_t pf, int optval, char __user *opt, 315 int *len); 316 #ifdef CONFIG_COMPAT 317 int compat_nf_setsockopt(struct sock *sk, u_int8_t pf, int optval, 318 char __user *opt, unsigned int len); 319 int compat_nf_getsockopt(struct sock *sk, u_int8_t pf, int optval, 320 char __user *opt, int *len); 321 #endif 322 323 /* Call this before modifying an existing packet: ensures it is 324 modifiable and linear to the point you care about (writable_len). 325 Returns true or false. */ 326 int skb_make_writable(struct sk_buff *skb, unsigned int writable_len); 327 328 struct flowi; 329 struct nf_queue_entry; 330 331 __sum16 nf_checksum(struct sk_buff *skb, unsigned int hook, 332 unsigned int dataoff, u_int8_t protocol, 333 unsigned short family); 334 335 __sum16 nf_checksum_partial(struct sk_buff *skb, unsigned int hook, 336 unsigned int dataoff, unsigned int len, 337 u_int8_t protocol, unsigned short family); 338 int nf_route(struct net *net, struct dst_entry **dst, struct flowi *fl, 339 bool strict, unsigned short family); 340 int nf_reroute(struct sk_buff *skb, struct nf_queue_entry *entry); 341 342 #include <net/flow.h> 343 344 struct nf_conn; 345 enum nf_nat_manip_type; 346 struct nlattr; 347 enum ip_conntrack_dir; 348 349 struct nf_nat_hook { 350 int (*parse_nat_setup)(struct nf_conn *ct, enum nf_nat_manip_type manip, 351 const struct nlattr *attr); 352 void (*decode_session)(struct sk_buff *skb, struct flowi *fl); 353 unsigned int (*manip_pkt)(struct sk_buff *skb, struct nf_conn *ct, 354 enum nf_nat_manip_type mtype, 355 enum ip_conntrack_dir dir); 356 }; 357 358 extern struct nf_nat_hook __rcu *nf_nat_hook; 359 360 static inline void 361 nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, u_int8_t family) 362 { 363 #ifdef CONFIG_NF_NAT_NEEDED 364 struct nf_nat_hook *nat_hook; 365 366 rcu_read_lock(); 367 nat_hook = rcu_dereference(nf_nat_hook); 368 if (nat_hook && nat_hook->decode_session) 369 nat_hook->decode_session(skb, fl); 370 rcu_read_unlock(); 371 #endif 372 } 373 374 #else /* !CONFIG_NETFILTER */ 375 static inline int 376 NF_HOOK_COND(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk, 377 struct sk_buff *skb, struct net_device *in, struct net_device *out, 378 int (*okfn)(struct net *, struct sock *, struct sk_buff *), 379 bool cond) 380 { 381 return okfn(net, sk, skb); 382 } 383 384 static inline int 385 NF_HOOK(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk, 386 struct sk_buff *skb, struct net_device *in, struct net_device *out, 387 int (*okfn)(struct net *, struct sock *, struct sk_buff *)) 388 { 389 return okfn(net, sk, skb); 390 } 391 392 static inline void 393 NF_HOOK_LIST(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk, 394 struct list_head *head, struct net_device *in, struct net_device *out, 395 int (*okfn)(struct net *, struct sock *, struct sk_buff *)) 396 { 397 /* nothing to do */ 398 } 399 400 static inline int nf_hook(u_int8_t pf, unsigned int hook, struct net *net, 401 struct sock *sk, struct sk_buff *skb, 402 struct net_device *indev, struct net_device *outdev, 403 int (*okfn)(struct net *, struct sock *, struct sk_buff *)) 404 { 405 return 1; 406 } 407 struct flowi; 408 static inline void 409 nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, u_int8_t family) 410 { 411 } 412 #endif /*CONFIG_NETFILTER*/ 413 414 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE) 415 #include <linux/netfilter/nf_conntrack_zones_common.h> 416 417 extern void (*ip_ct_attach)(struct sk_buff *, const struct sk_buff *) __rcu; 418 void nf_ct_attach(struct sk_buff *, const struct sk_buff *); 419 struct nf_conntrack_tuple; 420 bool nf_ct_get_tuple_skb(struct nf_conntrack_tuple *dst_tuple, 421 const struct sk_buff *skb); 422 #else 423 static inline void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb) {} 424 struct nf_conntrack_tuple; 425 static inline bool nf_ct_get_tuple_skb(struct nf_conntrack_tuple *dst_tuple, 426 const struct sk_buff *skb) 427 { 428 return false; 429 } 430 #endif 431 432 struct nf_conn; 433 enum ip_conntrack_info; 434 435 struct nf_ct_hook { 436 int (*update)(struct net *net, struct sk_buff *skb); 437 void (*destroy)(struct nf_conntrack *); 438 bool (*get_tuple_skb)(struct nf_conntrack_tuple *, 439 const struct sk_buff *); 440 }; 441 extern struct nf_ct_hook __rcu *nf_ct_hook; 442 443 struct nlattr; 444 445 struct nfnl_ct_hook { 446 struct nf_conn *(*get_ct)(const struct sk_buff *skb, 447 enum ip_conntrack_info *ctinfo); 448 size_t (*build_size)(const struct nf_conn *ct); 449 int (*build)(struct sk_buff *skb, struct nf_conn *ct, 450 enum ip_conntrack_info ctinfo, 451 u_int16_t ct_attr, u_int16_t ct_info_attr); 452 int (*parse)(const struct nlattr *attr, struct nf_conn *ct); 453 int (*attach_expect)(const struct nlattr *attr, struct nf_conn *ct, 454 u32 portid, u32 report); 455 void (*seq_adjust)(struct sk_buff *skb, struct nf_conn *ct, 456 enum ip_conntrack_info ctinfo, s32 off); 457 }; 458 extern struct nfnl_ct_hook __rcu *nfnl_ct_hook; 459 460 /** 461 * nf_skb_duplicated - TEE target has sent a packet 462 * 463 * When a xtables target sends a packet, the OUTPUT and POSTROUTING 464 * hooks are traversed again, i.e. nft and xtables are invoked recursively. 465 * 466 * This is used by xtables TEE target to prevent the duplicated skb from 467 * being duplicated again. 468 */ 469 DECLARE_PER_CPU(bool, nf_skb_duplicated); 470 471 #endif /*__LINUX_NETFILTER_H*/ 472